Switzerland has joined other nations in calling for the introduction of legally binding measures to enforce a global ban on biological weapons.
The appeal came on the opening day of an international conference in Geneva to review the 1972 Biological Weapons Convention.
Addressing the meeting, Swiss ambassador Jürg Streuli said the time had come for nations to strengthen the treaty to take account of present and future threats.
"This convention is by far the best framework in which to coordinate our efforts to confront the deliberate biological threat, whether this threat originates from a state or not," he said.
The convention, which bans the development and stockpiling of germ-based weapons, has never had serious enforcement measures because the threat of biological warfare was believed to be minimal when it was drafted during the Cold War.
Efforts to strengthen the treaty gathered pace after concerns that Iraq would use biological weapons during the Gulf War.
But talks were suspended in 2001 after the United States ended attempts to negotiate enforcement procedures, saying such a programme would give away defence secrets.
"[Switzerland] remains convinced that the drafting of an additional, legally binding protocol for the verification of the provisions of the convention should remain the goal of the conference," said Streuli.
Switzerland has drafted a working document designed to improve and strengthen confidence-building measures regarding verification mechanisms.
United Nations Secretary-General Kofi Annan said biological weapons posed a greater threat today owing to advances in science and technology.
Annan, who is on his last visit to Switzerland as UN chief, warned of the risks posed by biotechnology during a speech on Saturday in the eastern city of St Gallen where he received the Max Schmidheiny Freedom Prize.
Speaking in Geneva on Monday, he urged countries to build on progress made over the past five years and to "take further steps to ensure that the convention will continue to serve as an effective barrier against biological weapons".
Annan said the 31-year-old convention, with its emphasis on preventing states from developing biological weaponry, could not provide total protection on its own. Terrorism and crime at the non-state and individual level also had to be addressed.
He repeated a call for a new international forum bringing together governments, scientists, representatives of industry and the general public to develop a new strategy for facing up to the menace.
"The horror of biological weapons is shared by all," he said, urging the 155 states party to the treaty to overcome their differences and take further action over the three-week session.
The International Committee of the Red Cross also said on Monday that additional measures should be taken to exclude completely the possibility of biological agents and toxins being used as weapons.
swissinfo with agencies
The 1972 Biological and Toxic Weapons Convention has no provision for verifying whether its 155 member states are abiding by the treaty.
Public health experts say the most dangerous threats include lethal diseases such as smallpox, botulism, tularemia and anthrax, which killed five people when it was sent through the mail in the United States in 2001, and viruses such as Ebola.
The last review conference in 2001 collapsed amid disagreement over how to enforce the ban on biological weapons.