Transport Minister Ian Borg will undergo surgery to treat a rare knee condition in May but is set to continue campaigning following a two-day hiatus. 

On Monday the PL minister and electoral candidate said he was heading to London to treat the condition.

Borg suffers from what is known as pigmented villonodular synovitis (PVNS), a condition that leads to the swelling or growth of the lining of a joint.

It is a rare disease that has no definite cause and is most common between the ages of 30 and 40. Left untreated it can become very painful and damage nearby bones.

The 36-year-old posted a selfie outside an orthopaedic hospital in London, where he said he will be undergoing two interventions in the coming weeks.

"I can still work, although I was asked not to overdo it," he said. "I'll try."

Borg said there were several ways of treating the disease but that he had opted for surgery.

He thanked all those who had contacted him with messages of support, with more than 8,000 people commenting below his Facebook page.

His political rival, shadow Transport Minister Toni Bezzina was among those to share their messages of support. 

Several days ago Bezzina posted a picture of the two of them together on Facebook.

"Despite the political differences between us, when it comes to health we should never look at political colours," he said.

"I look forward to meeting again in the coming days and continuing to come up with ideas for the good of the Maltese and Gozitan people."