A Perth company has pulled out of providing hooks and marine supplies to the State Government's drum-line program after being targeted by anti-shark cull protesters.

Amid escalating rhetoric by opponents of the contentious policy, The Weekend West has learnt Taylor Marine informed the Government this week it could no longer continue supplying the program after protesters discovered the company's identity, sparking concern for the safety of its staff and property.

The Henderson business had provided products including the large hooks and swivels used as part of last summer's drum-line trial.

It is believed Taylor was paid about $70,000 for the materials.

It is understood the Government will have to look interstate or overseas for a supplier.

Divisions over the drum-line policy were reopened this month when the Government referred a proposal to extend it for another three years to the State's environment watchdog.

The move, which will be accompanied by a public submission period, acted as a call to arms for opponents of the policy.

Although Taylor Marine was unavailable to comment on the revelations, it is understood the company had been subjected to threats and intimidation over recent months.

In comments posted on social networking sites, activists protesting the drum-line policy proclaimed Taylor's decision as "a small win" for their movement.

Taylor's withdrawal came after the group leading the charge against the Government's policy vowed to step up its campaign to overturn it.

Yesterday, a small number of protesters tried to hand-deliver a petition to Environmental Protection Authority chairman Paul Vogel but were unable to.

During a radio interview with the ABC on Thursday, Colin Barnett fielded a call from noWAsharkcull member Simon Blears in which he warned the Premier "the gloves are off".

"We played nice last time and the gloves are off," Mr Blears said. "We are not going to be so nice this time."

Mr Blears had written about the need to identify suppliers to the Government's drum-line program - and named Taylor - "to tell them that we don't approve".