First determine whether they are a ‘broadleaf’ weeds or ‘grass-type’ weeds.
If you mainly have broadleaf weeds, then Bow & Arrow or BroadForce MA herbicide would be the safest options for your lawn.
Both products will control many of the common broadleaf weeds.
If some weeds remain, a more accurate identification of the weed will be required.
Also make sure you add a sticker such as Wetter 600 in with your herbicide to ensure good results.
If you mainly have grass-type weeds, this can be a little more difficult. The best strategy is prevention, by applying a ‘pre-emergent’ herbicide such as Oxafert before the weeds appear.
Barricade & Spartan are liquid pre-emergents giving you up to 6 month barrier against new weed germination.
However if you already have grass-type weeds, dig them out first and then apply the pre-emergent.
Oxafert at 4kg/100m2 using a suitable spreader, or Barricade or Spartan at 40mL/100m2 using suitable spray equipment in spring, summer and autumn, to prevent them coming up again.
Oxafert has the advantage of being both a pre-emergent herbicide and fertiliser, so it will prevent weeds while improving turf health at the same time!
Keep your lawn healthy to out-compete the weeds through regular fertiliser applications (e.g. refer Scenario 3), and mow at least weekly during warmer months.