Frontier said the 13,000 metre drilling program was previously delayed due to weather and mobilisation issues.

Two rigs are expected to be barged, and then flown by helicopter to drill sites at the Likuruanga gold-copper project in East New Britain this month.

The first hole is targeting an old BHP exploration site to a 600m depth and drilling is expected to start around August 19-20.

Another two rigs are destined for the Bulago gold project in the highlands as "rapidly" as weather conditions allow, Frontier says.

OTML plans to shift into "advanced stage exploration" for these two projects, along with the Leonard Schultz gold project, according to Frontier.

A trenching and sampling program is planned for the Leonard Schultz project with a field team expected to mobilise around August 22.

Frontier's main focus in PNG is its Andewa copper-gold project, and the 10,000m diamond core drilling program, which started last month, just completed its first hole last week at a depth of 398.8m.

The explorer has purchased four additional rigs, to boost its existing fleet of two rigs, just for its Andewa project.

Frontier said the four rigs were recently shipped over from China, along with two excavators, 2 bulldozers and supporting machinery and vehicles.

Frontier shares are down half a cent to 20.5c this morning.