Played at Proctor Park in Bathurst, Mariners found themselves trailing 3-0 at the break in their NSW National Premier Leagues 3 match, before the visitors scored two more goals in the second-half.

It's the sides fifth consecutive loss, after losing to Camden Tigers, Hawkesbury City, Inter Lions and SD Raiders.

Mariners coach Mark Rooke said his side's first half performance was disappointing.

"Our second half was the best part of the game," he said.

"I can't put my finger on it but the past three games, our first half has been horrible. It's not up to the standard we want. We're just not executing our game plan."

Rooke said his side had several good chances in the second half and were originally awarded a penalty, which was later reversed to a free kick on the edge of the box after a big protest from the Dulwich Hill players.

"It's just our luck at the moment, not getting the rub of green with the calls," he said.

The result keeps the Mariners in last place on six points and second-last in the club championship, the deciding factor in relegation at the end of the season.

Due to a restructure in the Football NSW pyramid, the bottom five teams in the NSW NPL 3 club championship will be relegated to the NSW State League.

The Mariners last tasted success in May, when they claimed a 4-3 win over Sydney University.

The Mariners will be on the road for their next two matches - Gladesville Ryde Magic on June 23 at Christie Park and Bankstown United on June 29 on Jensen Park.