The king indicated before the start of his six-day state visit that while he could not interfere in politics he was keen to ask Howard a couple of questions about Australia's refusal to sign the protocol, which aims to reduce the emission of greenhouse gases.

"I don't interfere, but I can always raise the question -- it's not forbidden to ask a question," the Swedish monarch told Australian reporters in an interview at his palace ahead of the trip.

But at Monday's parliamentary lunch, King Carl XVI and Howard restricted their public comments to praise for each others' countries.

Howard said Sweden was a successful, modern nation with a strong economy and there existed a "great friendship between our two countries".

King Carl XVI, on his second state visit to Australia after a 1982 tour, said Australia and Sweden were "like-minded in many ways."

"It is hard to imagine two countries so far apart geographically as Australia and Sweden. Still we have close bonds in many areas where we enjoy fruitful cooperation," he said.

In the interview, however, the king and Queen Silvia showed keen interest in global warming and the fact that Australia, along with the United States, has refused to ratify the Kyoto Protocol.

Australia is the world's biggest exporter of coal, one of the fossil fuels responsible for carbon dioxide emissions, which industrialised countries are bound to trim under the protocol.

The queen twice asked whether the Howard government had any intention of ratifying the protocol, and the king said he might raise the issue with the prime minister.

"We will see. All possibilities are there. We can ask the question," he said, indicating his own belief that global warming posed a serious threat.

The Sydney Morning Herald had some advice for Howard, and a little irreverence for the king and queen, in a light back-page column Monday.

"Last night some old bloke who runs a cold European country and his sheila (girlfriend/wife) landed at Sydney airport and stayed at a hotel in the city," the paper said, before referring to the question about the signing of the protocol.

"Mr Howard, the Swedish word you're looking for is 'nej'. Repeat as necessary."

The king said at the luncheon he hoped the visit, which will focus on information technology, environmental issues and using technology to treat health problems, would lead to increased investment between the countries.

The royal couple, who last visited Australia in 2000 for the Sydney Olympic Games, were due to attend a state dinner at Government House later Monday.

They will also visit Sydney, Perth, Adelaide and central Australia.

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