LONDON (REUTERS) - British Prime Minister Theresa May will visit China this year to discuss trade ties, the latest in a series of foreign trips to cement relations with major powers as she negotiates Britain's divorce from the European Union.

May's aides gave few details about the trip, but she is keen to strengthen her hand by securing foreign support before launching Brexit talks, which are set to be among the most complicated Britain has ever undertaken.

"It would be a renewed expression of the close relationship between Britain and China, something that you have seen obviously develop over the past few years," May's spokesman told reporters on Tuesday (Feb 7).

"I would imagine that trade would form some part of the discussions that we have."

May attended a summit in China of the Group of 20 leading economies last September, shortly after she became prime minister following June's referendum vote to leave the EU, and was invited by President Xi Jinping to visit again.

With May having made clear she plans for Britain to leave the EU's single market, trade has dominated her talks with foreign leaders in recent months.

She has secured assurances from US President Donald Trump, Indian Prime Minister Narendra Modi and other world powers that they are keen to start talks on boosting links.

But her attempts to up the stakes in talks with the EU, which she is due to launch before the end of March, have also drawn criticism.

Some opposition lawmakers have accused May of ducking difficult issues to win promises for trade - a charge repeated when she became the first foreign leader late last month to meet Trump, who has since been criticised over his immigration curbs.

She also came under fire for strengthening ties with Turkish President Tayyip Erdogan, who has been criticised by rights groups for jailing tens of thousands of people after a failed coup in July.