Republican John McCain got a rough ride on the plush couch of a top US daytime talk show, forced to deny his negative attacks on White House foe Barack Obama amounted to "lies".

McCain ventured onto the set of The View, a morning show aimed at women, and faced a grilling on his vice-presidential pick Sarah Palin, abortion policy and his recent barrage of attack ads aimed at Obama.

IN DEPTH: Dateline's coverage of the US elections

RELATED: The McCain Train

ANALYSIS: The Democratic Campaign
ANALYSIS: The Republican Campaign

YOUR SAY: Will Sarah Palin make, or break, the Republican campaign?

The Arizona senator defended his campaign's claim that his Democratic opponent called Palin a "pig" and advocated teaching sex education to kindergarten children.

"Actually, they are not lies," McCain said during the exchange with the show's hosts, led by veteran news host Barbara Walters and comedian Whoopi Goldberg.

The Obama campaign says McCain's camp deliberately misinterpreted Obama's recent comment that Republican claims to represent change were like putting "lipstick on a pig" as a sexist remark aimed at Palin.

"He shouldn't have said it. He chooses his words very carefully, this is a tough campaign," McCain said.

McCain was later joined by his wife Cindy on the set of the show, which has sometimes been criticised by conservatives for liberal bias.

"You used to be sort of the maverick. Then you sort of turned," said co-host Joy Behar, prompting McCain to mount a fierce defence of qualities his campaign hopes distinguish him from his unpopular party.

"What specific area have I, quote, changed?" McCain asked. "Nobody can name it."

"The point is I'm the same person with the same principles, whether spending, climate change, the conduct of the war in Iraq, torture of prisoners.

"No matter what it is - I'm the same guy."

Chosen running mate questioned

Walters assailed McCain over his choice of first term Alaska governor Palin as running mate, asking what exactly she was going to reform.

"The Republican Party. The Democratic Party. She's going to reform all of Washington," McCain said.

The audience later booed McCain when he said the landmark 1973 Roe v Wade Supreme Court decision permitting the right to have an abortion was wrong.

There was some respite for the Republican, however, as the show aired footage of his return to the United States after five-and-a-half years in a Vietnam war prison camp, highlighting the heroic biography on which McCain has partly based his campaign.

Easier ride

McCain got an easier ride on another daytime show, presented by famed television chef Rachael Ray, and vowed to install a barbecue grill at the White House and Camp David presidential compound if elected on November 4.

"I don't want to get into too much politics," the Arizona senator said, who in the days of happier relations with his travelling press corps entertained reporters at his Arizona retreat.

"The reason I love the grill? It's a social occasion," he said.

"It's one of my main source of enjoyment."

Advertising war

McCain this week launched a flurry of attack ads as he enjoyed a wave of momentum after the conservative grassroots embraced Palin's nomination at the Republican convention.

Earlier this week, the McCain campaign debuted an attack ad claiming that as a state politician in Illinois, Obama backed a bill to teach "comprehensive sex education" to children in kindergarten.

"Learning about sex before learning to read? Barack Obama. Wrong on education. Wrong for your family," the narrator of the advertisement said.

In reality, the legislation allowed local schools to teach "age-appropriate" sex education, meaning that kindergarten kids could be warned about sexual predators and inappropriate touching, but not taught about sex.

The Obama camp hit back angrily at McCain over the advertisement.

"It is shameful and downright perverse for the McCain campaign to use a bill that was written to protect young children from sexual predators as a recycled and discredited political attack against a father of two young girls," said Obama campaign spokesman Bill Burton.

"Last week, John McCain told Time magazine he couldn't define what honour was. Now we know why."

The intense McCain barrage has prompted the Obama campaign to launch a counter-attack, with ads which branded McCain as out of touch with the economic travails of everyday Americans and guilty of using smears against the Democrat.