An Australian, a Briton and two New Zealanders have been jailed for four weeks each in Singapore for selling forged tickets to an Ed Sheeran concert.

The Australian, 56-year-old Paul Cosgrove, was sentenced Wednesday after admitting that he abetted Briton Martin Keane in a scheme to sneak fans into the British singer-songwriter's sold-out concert in the city-state using the fake tickets.

Keane, 60, was jailed last month after pleading guilty to his role in the crime, alongside two men from New Zealand, Scott Penk and Michael Hardgrave, who also admitted to selling forged tickets to the November 12 concert.

In the first case, Cosgrove gave fake passes to Keane, who used them to take fans past security into the stadium where the concert was taking place, charging them Sg$250 to Sg$300 (US$185 to US$220) each, according to court documents.

The official price of tickets for the concert was between Sg$108 and Sg$248. Sheeran played two dates in Singapore, on November 11 and 12, as part of his tour of Asia.

Keane took four fans into the concert on two separate occasions but was stopped on his third attempt by security staff, who discovered he was using a fake ticket and detained him.

Cosgrove was caught 10 days later by immigration officials as he attempted to cross into neighbouring Malaysia.

The pair from New Zealand obtained several forged passes outside the November 12 concert from unknown individuals.

Hardgrave, 30, used them to bring several fans into the stadium in exchange for a fee before he and Penk, 34, were spotted by security staff and detained.